Our recommendation is to use 100% pure spring water. Since water does make up over 90% of your teas ingredients it would be exceptionally important to be carefull with the water you chose to use. Unfortunately, in most countries tap water is poor and in some cases even dangerous containing high levels of hazardous materials. These materials do not add flavor to your tea and may eliminate some of the health benifits you would have from drinking the tea. There are obvious health reasons, but it will affect the taste of your tea. It would be a shame to use an exceptional variety of tea or an organic herbal tea and get a mediocre results because of poor water.